From The Art and Popular Culture Encyclopedia

In Ovid's Metamorphoses, Acis was the spirit of the Acis River in Sicily, beloved of the nereid, or sea-nymph, Galatea ("she who is milk-white"). Galatea returned the love of Acis, but a jealous suitor, the Sicilian CyclopsPolyphemus, killed him with a boulder. Distraught, Galatea then turned his blood into the river Acis. The Acis River flowed past Akion (Acium) near Mount Etna in Sicily.